ABSTRACT
Abstraction of groundwater resources is increasing over the years to meet its ever-increasing demand for industrial, agricultural and domestic purposes throughout the world. The scenario is even worse in the east flowing rivers of the Western Ghats, where the demand of water is high under changing climatic conditions. Such situation may affect the groundwater resources of the river basin on a long run. The aim of the present study is to characterize the geochemistry of groundwater in Tamiraparani sub-basin through geochemical modeling and deduce the ionic interactions with the aid of geostatistical and multivariate statistical techniques. A total of 40 groundwater samples from shallow aquifers were collected randomly throughout the sub-basin for assessing its physico-chemical parameters, which include physical properties of the water, major ions and nutrients. Two major hydrogeochemical facies were identified such as mixed Ca-Mg-Cl and Ca-HCO3 groups. The nutrients derived from agricultural runoff, urban discharge and organic decomposition alters the nutrient level in the groundwater. The dissolution/precipitation of minerals such as calcite and dolomite controls the chemical constituents of the groundwater. The multivariate statistical analysis indicates that natural weathering of source rocks is the main contributors of ions in the groundwater followed by anthropogenic activities such as agricultural practices and urbanization. The insights obtained from this study can be helpful for sustainable groundwater management and long-term monitoring studies.